Use a fishbone to identify potential causes of an effect. A fishbone
is also called a cause-and-effect (C&E) diagram or an Ishikawa diagram.
Watch this video to learn more:
On a fishbone, the effect, or central problem, is on the far right.
Affinities, which are categories of causes, branch from the spine of the
effect. Causes branch from the affinities. By default, affinities and causes
are expanded so that you can view all levels of the fishbone.
Answers the questions:
What are the potential causes
for a particular type of defect?
What are the process inputs
that contribute to variation in the process output?
When to Use
Assist in project identification by linking potential causes to
Start of project
Assist in problem identification.
Identify potential process inputs to investigate in the project to
determine which inputs have a significant influence on the process
This tool has no data requirements because you use it only to collect and
Be sure to include project
stakeholders in the brainstorming sessions for building the fishbone diagram.
If the standard categories
of the causes are not appropriate for the problem, create new ones. For
example, service-quality applications often include personnel, procedures, and
policies. However, fishbone diagrams can include any type of cause you want to
Gather the project team and
appropriate stakeholders for a brainstorming session.
Determine the primary
categories (affinities) for the causes of the problem (for example, personnel,
machines, methods, materials, measurements, and environment).
For each primary category,
list all possible causes or process inputs. You may want to establish secondary
categories for some or all of the primary categories, then list the causes or
process inputs under the secondary categories.
Highlight causes (or inputs)
that are deemed to be the most important by the team.
Record the categories and
causes, using the fishbone tool.